Flutemetamol (18F) Injection is an agent used for visualizing β-amyloid beta plaques in the brain by positron emission tomography, and is useful in diagnosis of Alzheimer type dementia.
As a method for producing [18F]flutemetamol, for example, using a radiopharmaceutical synthesizer “FASTlab”, a method of reacting AH111907 (6-ethoxymethoxy-2-(4′-(N-formyl-N-methyl)amino-3′-nitro)phenylbenzothiazole) with a radioactive fluoride to replace the nitro group of AH111907 by 18F, then converting AH111907 residue into a less fat-soluble substance by a strong base, removing protective groups of the hydroxy group and amino group of the 18F substitution product of AH111907 (6-ethoxymethoxy-2-(4′-(N-formyl-N-methyl)amino-3′-[18F]fluoro)phenylbenzothiazole), then performing purification using a solid phase extraction cartridge is known (WO2011/044406).
However, the yield of [18F]flutemetamol is low in the method described in WO2011/044406, thus, delivery to a wide range by mass production has been difficult. Therefore, in order to supply [18F]flutemetamol formulation to more patients, it has been required to improve productivity.